It is well known in the art of hearing aids to have multiple modes of operation, such as different directional characteristics and different methods of noise suppression. The purpose of the different modes of operation is to suit the wearer's needs as good as possible in different environments and situations. As an example, directionality makes it possible for a hearing aid to “focus” on a sound source, such as a speaking person, located e.g. in front of the wearer of the hearing aid. Thereby, possibly disturbing sounds coming from the sides and back of the wearer will have a limited influence on the wearer's perception of sound from a source in front of him/her.
Since it is quite inconvenient for a hearing impaired person to manually switch between different modes of operation in dependence of his/her needs, several attempts have been made to develop efficient methods for automatically selecting “the best” mode of operation as the listening environment or conditions changes. See e.g. published international patent application WO 01/76321 for an example of this.
Another example of such an automatic selection algorithm was presented by Starkey Laboratories, Inc. at the Union der Hörgeräte-Akustiker (UHA) fair in Nürnberg (Germany) in October, 2003. It was stated that “the omni-directional mode is activated in environments with good signal to noise ratio and the directional mode is activated in environments with poor signal to noise ratio”.
Recently, research has shown that hearing aid users prefer a directional mode of operation over an omni-directional mode primarily when they find themselves in a noisy environment and there is a speech source in front of them at a fairly close range, e.g. 2-3 meters. These research results was presented on 1 Feb. 2003 by Brian E. Walden, Ph.D., Director of Research, Army Audiology & Speech Center, Walter Reed Army Medical Center at The First Annual Southern California Conference on Speech, Language, And Hearing Sciences under the title: “Predicting Hearing Aid Microphone Preference in Everyday Listening”.